Differences between Mitosis and Meiosis.pptx

SCIENCE 8

1. Differences between Mitosis and Meiosis

2. Review: H ow will you going to differentiate the two-cell division?

3. Mitosis is a type of cell division that results in two identical daughter cells with the same number of chromosomes as the parent cell. Meiosis is a special type of cell division that produces four genetically different daughter cells with half the number of chromosomes as the parent cell.

4. Activity 1: Comparing Mitosis and Meiosis! Directions: Identify if the different characteristics and roles by saying if it is mitosis, meiosis or both.

5. Produces body cells Mitosis 2. Ensures genetic stability Mitosis 3. Divides the parent cell once Mitosis 4. Divides the parent cell twice Meiosis 5. Produces four daughter cells Meiosis 6. Gives way to genetic diversity Meiosis

6. 7. Produces gametes or sex cells Meiosis 8. Produces daughter cells with same number of chromosomes like the mother cell Mitosis 9. Aids in the repair of genetic defects M ito sis 10. Associated with sexual reproduction Meiosis

7. 11. Associated with asexual reproduction Mitosis 12. Produces two identical daughter cells Mitosis 13. Occurs in the gonads (testes and ovaries) Meiosis 14. Produces diploid or haploid daughter cells Both 15. Helps in the repair of damaged cells/tissues Mitosis

8. In eukaryotes, two types of cell divisions exist:  mitosis  and  meiosis . While these processes are similar in principles, they also have distinct characteristics and roles. Below, are the said differences and roles of mitosis and meiosis .

9. Table 1. Differences in Characteristics between Mitosis and Meiosis Characteristics Mitosis Meiosis Location Somatic cells Somatic cells Chromosome number of parent cell Diploid (2n) or haploid (n) Diploid (2n) Chromosome number of daughter cell Diploid (2n) or haploid (n) Haploid (n) Number of daughter cells produced Two Four Number of nuclear divisions One Two Steps required to complete the cell division phase Prophase, Metaphase, Anaphase, and Telophase Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, and Telophase II Occurrence of synapsis None Yes Occurrence of crossing over None Yes Presence of chiasma Absent Present Kind of reproduction associated with Asexual Sexual

10. Table 2. Roles of Mitosis and Meiosis in the Cell Division Mitosis Meiosis 1. For somatic or body cell production - The repeated cell division through mitosis increases the number of somatic cells which is important for the growth of organisms. 1. For gametes or sex cell production - The diploid parent sex cells divide twice resulting to four genetically different haploid (N) daughter cells. 2. For asexual reproduction - Unicellular (single-celled) organisms reproduce fast and easily by mitosis that will result to the production of genetically identical offspring. Among plants, reproduction is also possible through cloning, grafting and marcotting, all of which do not involve gametes. 2. For sexual reproduction - Most multicellular organisms start as a single cell – a fertilized egg known as zygote. This zygote is the result of fertilization or the union of a female gamete, an egg, with a male gamete, a sperm that are produced through meiotic cell division.

11. Table 2. Roles of Mitosis and Meiosis in the Cell Division Mitosis Meiosis 3. For genetic stability - During mitosis, the resulting two daughter cells have the same type and number of genes as the original parent cell, thereby preserving and maintaining the genetic composition of a particular population 3. For genetic diversity - Complex or multicellular organisms produce gametes that contain only one half of the information carried by the parent gamete. During fertilization, these gametes unite allowing genes from each parent to combine which results to differences in the DNA sequences of offspring. 4. For the repair of damaged cells/tissues - Mitosis helps in the repair of worn-out body cells and replaces damaged cells and tissues through repeated cell division 4. Aids in the repair of genetic defects - Meiotic recombination is also used in DNA repair, whereby pieces of DNA are broken and recombined to produce new combination of alleles (form of gene). Recombination replaces defective gene with the healthy allele giving way to healthy offspring.

12. Activity 2: Create a model of both mitosis and meiosis ! Direction: Demonstrate the steps of mitosis and meiosis visually by creating a model of these processes. The model must be accurate, demonstrate knowledge of the information (describes what happens in each phase), and be a creative design. It must be a 3D model and cannot be a poster or drawing on paper. This will serve as your science project and will be graded on knowledge, accuracy, creativity, and neatness. Please be guided on the given rubrics.

13. You will be graded according to the rubrics. Possible Points 100% 75% 50% 25% 0%       40 pts Knowledge Project demonstrates a clear understanding of meiosis and mitosis and correctly illustrates each of the phases. It is easy for an observer unfamiliar with mitosis to understand the process. Project demonstrates a good understanding of meiosis and mitosis and correctly illustrates most of the phases. An observer unfamiliar with mitosis would probably understand the process. Project demonstrates a limited understanding of meiosis and mitosis and incorrectly illustrates or does not include all phases. An observer would have a difficult time understanding the process. Project shows little or no understanding of mitosis and meiosis and does not correctly illustrate any phase. Project is NOT done! 30 pts Accuracy Project demonstrates a high level of accuracy Project demonstrates some accuracy, but resembles other projects. Project demonstrates limited accuracy. Project shows no accuracy. Fact based poster or PowerPoint. Project is NOT done! 20 pts Creativity Project demonstrates a high level of creativity and originality. Project demonstrates some creativity and originality, but resembles other projects. Project demonstrates limited creativity and originality. Project shows no creativity or originality. Fact based poster or PowerPoint. Project is NOT done! 10 pts Neatness Final project is neat and shows care and time was spent developing it. Final project shows some carelessness and little time were spent developing it. Final project shows carelessness and very little time was spent developing it. Final project is sloppy and looks like it was rushed at the last minute. Project is NOT done!

14. Samples in creating a Model for Mitosis : A B C

15. Samples in creating a Model for Meiosis : A B C

16. Materials needed: ¼ illustration board Plastic cover Clay or foam board Glue or stick glue Color paint of colored paper Pentel pen or any coloring pen

17. Teacher’s expectation: 3D MODEL OF MITOSIS AND MEIOSIS MITOSIS MEIOSIS Prophase Meiosis I Meiosis II Metaphase Prophase I Prophase II Anaphase Metaphase I Metaphase II Telophase Anaphase I Anaphase II Telophase I Telophase I Submitted by: Name of group members Submitted to: STINELIE C. BATICAN Science Teacher

18. Directions: Complete the Ven diagram below by writing the differences and similarities of mitosis or meiosis. Write your answers on a separate sheet of paper. Mitosis Meiosis Similarities Word Choices: Starts with diploid cells 2n  2n 2n  n DNA replication occurs Diploid  diploid Diploid  haploid Daughter cells identical Same basic steps One division Two division Makes new cells Daughter cells genetically different Daughter has 46 chromosomes Daughter cells has 23 Chromosomes align Homologous pairs align Gor growth and repair Makes sex cells (egg and sperm cells)